package org.huntaway.hadoop;

import java.io.IOException;
import java.util.StringTokenizer;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Mapper.Context;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.TextInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
import org.apache.hadoop.mapreduce.lib.output.TextOutputFormat;

public class WordCount {
	public static class Map extends Mapper<LongWritable, Text, Text, IntWritable> {
	     private final static IntWritable one = new IntWritable(1);
	     private Text word = new Text();
	         
	     public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
	         String line = value.toString();
	         StringTokenizer tokenizer = new StringTokenizer(line);
	         while (tokenizer.hasMoreTokens()) {
	             word.set(tokenizer.nextToken());
	             context.write(word, one);
	         }
	     }
	  } 
	         
	  public static class Reduce extends Reducer<Text, IntWritable, Text, IntWritable> {
	 
	     public void reduce(Text key, Iterable<IntWritable> values, Context context) 
	       throws IOException, InterruptedException {
	         int sum = 0;
	         for (IntWritable val : values) {
	             sum += val.get();
	         }
	         context.write(key, new IntWritable(sum));
	     }
	  }
	         
	  public static void main(String[] args) throws Exception {
	     Configuration conf = new Configuration();
	         
	         Job job = new Job(conf, "wordcount");
	     
	     job.setOutputKeyClass(Text.class);
	     job.setOutputValueClass(IntWritable.class);
	         
	     job.setMapperClass(Map.class);
	     job.setReducerClass(Reduce.class);
	         
	     job.setInputFormatClass(TextInputFormat.class);
	     job.setOutputFormatClass(TextOutputFormat.class);
	         
	     FileInputFormat.addInputPath(job, new Path(args[0]));
	     FileOutputFormat.setOutputPath(job, new Path(args[1]));
	         
	     job.waitForCompletion(true);
	  }
	     
}
